The human circulation is a complex system that has evolved over millenia, primarily designed to promptly respond to conditions of stress - the fight and flight response. The traditional physiological approach focuses on the heart as a pump, adapting to changes in volume and metabolic states.

These principles are underpinned by the Starling equation and incorporated into an adaptation of Ohm\'s law. These principles have been maladapted, punctuated by an increasing reliance on surrogate and derived variables that have little to do with teleological haemodyanamic responses.Insights into the central role of the autonomic nervous system are provided by Guytonian theory that in part explain the physiological fallacy germane to many clinical protocols and practices.

These fallacies have been amplified by commercial studies directed at short-term physiological improvements that have little to do with patient-centred outcomes in the medium and longer term.Such effects have been demonstrated in recent high-quality RCTs that force a re-appraisal of seductive short-term physiologically-based gratification.